Commercial airlines have recently begun providing telephone service to passengers. Typically, an aircraft cabin contains a number of seatbacks that incorporate handsets from which passengers may place calls using credit cards or other payment mechanisms. These handsets are usually hard-wired to the seatbacks and are connected to a central communication control system in the aircraft.
The use of hard-wired handsets in seatbacks, however, presents several problems. Physical wires must be strung from the central communication control system to each of the seatbacks selected for handset placement, resulting in potential difficulties in installation and/or maintenance. Additionally, since the handsets are hard-wired to the seatbacks, a passenger using one of the handsets will likely be restricted in movement by the attached cable connecting the handset to the seatback. As another disadvantage, because many such systems require several passengers to share a single handset, the ability of adjacently seated passengers to simultaneously place calls is limited. Finally, these systems typically only allow passengers to place calls, and do not enable passengers to receive incoming calls.
Recently, other solutions have been proposed to overcome the shortcomings of these hard-wired aircraft phones. These solutions address such issues as allowing a customer to place or receive calls using the customer's own handset. These more recent proposals, however, still suffer from various problems.
U.S. Pat. No. 5,995,833 sets forth a system in which one or more base stations are implemented in an aircraft. While purporting to enable a passenger to use a subscriber-provided radio telephone, this proposal does not indicate how to avoid possible interference with the aircraft's flight control and communication system. The system's use of base stations involves much more than simple relays or repeaters, and instead may use communications equipment that is “intelligent” in the sense that modems, switches, and other devices perform different functions depending on the identity of the users. The use of base stations may also make this proposal relatively expensive.
U.S. Pat. No. 5,519,761 sets forth a first proposal that includes a base station in the aircraft, and a second proposal that does not require such a base station. Neither of these proposals addresses the issue of possible interference with the aircraft's flight control and communication system.
U.S. Pat. No. 5,887,258 sets forth a proposal in which a personal means of radio communication, such as a mobile telephone, may be modified to accept a cable that plugs into an aircraft communication system. While this proposal may address electromagnetic interference with the on-board electronic systems of the aircraft, the use of the cable reduces portability, making this proposal somewhat inconvenient.
These proposed solutions are largely silent on avoiding possible interference with an aircraft's flight control and communication system. Additionally, compliance with applicable aviation regulations may be complicated by the use of copper or other metallic conductors, such as coaxial cable, set forth in some of these proposals. Besides acting as possible antennas, these metallic conductors may present a risk of sparking thereby posing a potential fire hazard and serving as an additional potential source of RF interference.
Aircraft instrumentation is often extremely sensitive so that potential interference must be carefully controlled. Because relatively long lengths of wire and cable are often bundled together due to space constraints in an aircraft, the possibility of interference is magnified.
Thus, there is a need for a wireless communication system that enables a passenger to utilize a wireless handset on an aircraft without requiring hard-wired connections to the handset. Such a system should not necessarily require a base station in the aircraft. The system should be designed to avoid any possible interference with the aircraft's flight communication and control system, and should not significantly increase the likelihood of fire or explosion with the aircraft.